A two-stage master cylinder is illustrated in U.S. patent application Ser. No. 832,134, now U.S. Pat. No. 4,170,386. A housing defines a reservoir and a bore which movably receives a pair of pistons. One of the pistons carries a valve member and cooperates with the housing to define a fast-fill chamber. During a braking application, fluid pressure trapped within the fast-fill chamber is communicated to the primary chamber via the valve member. When a predetermined pressure level is reached in the primary chamber, the valve member operates to dump the fast-fill chamber to the reservoir. When the fast-fill chamber is dumped a transition occurs for the effort required to actuate braking. Prior to dumping, pedal effort is utilized to generate fluid pressure in the fast-fill chamber as well as in the primary chamber. After dumping, pedal effort is only required to generate fluid pressure in the primary chamber. Consequently, a decrease in pedal effort is felt by a vehicle operator upon dumping of the fast-fill chamber to the reservoir.